The overall objective of the proposed research is to identify parameters which can be measured to provide earlier and more accurate diagnosis, and ensure improved treatment, management, and assessment of prognosis in patients with lung cancer. It is planned to accomplish this through the following specific methods and objectives: 1. To identify human lung cancer plasma membrane tumor-associated antigens (TAA's) which are absent from normal adult tissue and from cancers of other organs; to determine the occurrence of these TAA's in the different histologic types of human lung cancer and in various premalignant conditions of the respiratory tree. One such antigen associated with oat cell carcinoma of the lung has been identified. Other TAA's will be identified by two different approaches. The first involves planned immunization of rabbits and monkeys with human lung cancer plasma membranes and assay of the immune sera by indirect immunofluorescence assay. The second utilizes the host's own immune response to his tumor: appropriately treated host sera will be assayed by indirect immunofluorescence; host leukocyte reactivity to crude lung cancer antigens will be assayed by leukocyte adherence inhibition. 2. To determine the occurrence and concentration of these TAA's in the sera and respiratory secretions of patients with various malignant, premalignant, and benign conditions. The TAA's will be solubilized and purified, and a radioimmunoassay developed to determine the above. 3. To determine the occurrence of cellular and humoral immunity to these defined TAA's, and of specific blocking factors related to these TAA's in patients with various malignant, premalignant, and benign conditions. A leukocyte adherence inhibition assay and a double antibody primary binding assay will be developed to determine the above. 4. To determine the relationships of the occurrence of these parameters to the different stages of human lung cancer.